The field of the invention relates generally to multi-chambered pumps and methods of operating the same, and more specifically, to a multi-chambered pump for pumping a source substance into a vessel and harnessing the pressure associated with an effluent output from the vessel to aid in pumping additional quantities of the substance into the vessel.
While reference is made herein to source substances comprising slurries and multi-chambered pumps referred to as slurry pumps, these examples should not be construed as limiting the scope of the embodiments. Rather, the systems and methods described herein are applicable to a wide range of substances and multi-chambered pumps.
A slurry (i.e., a source substance) is a watery mixture of insoluble matter. Examples of slurries include: mud, lime, unset plaster of paris, and mixtures of manure and other liquids. In some refining operations, slurries are pumped into a vessel (e.g., a process reactor) where a chemical reaction transforms the slurry into a chemically different composition (i.e., an effluent). The chemical reaction that takes place in the process reactor often requires the slurry to be input at an elevated pressure (e.g., 100 atmospheres), and likewise results in the effluent being expelled from the process reactor at a pressure slightly lower than it was input.
The utilization of traditional slurry pumps (e.g., piston-type reciprocating pumps) to pump the slurry into the process reactor requires the use of valves (typically check valves) to maintain the elevated pressure within the process reactor during the different phases of the pumping cycle. The valves control both the inlet and outlets of the process reactor to maintain an elevated pressure therein during a pumping cycle of the piston-type reciprocating pumps. The valves are not capable of reliably controlling the high-pressure flow of the slurry due to the solids suspended therein. The solids erode the seals and seats within a valve, often leading to premature failure of the valve. Additionally, the valves can be prevented from fully closing if a piece of the solid becomes lodged between a valve member and its corresponding seat.
Due to the closed system design of certain process reactors, effluent is expelled from the process reactor at an elevated pressure, although it is often slightly less than the pressure at which the slurry was input to the process reactor due to, for example, frictional losses within the process reactor. Generally, the energy contained in the elevated pressure effluent flow has not been harnessed, as the effluent is simply discharged to a holding tank or other receptacle. Further, as the effluent may still contain solids disposed therein, the same problems are encountered in metering the flow with valves as those experienced in metering the input of slurry.
Accordingly, an improved pumping system and method are needed to reliably control the input and output of slurry from a process reactor at an elevated pressure and harness the elevated pressure of the effluent flow to aid in the pumping of additional slurry into the process reactor.